PROJECT SUMMARY ABSTRACT Tens of thousands of Americans with end stage lung disease (ESLD) are not candidates for lung transplant and thus are doomed to suffer a long and miserable death from dyspnea, limitation of activity, and eventually total respiratory failure. The long-term goal of this technology-development project is to improve the quality of life of end stage lung disease (ELSD) patients by developing wearable artificial lungs that compensate for the changing metabolic needs of the patient. The objectives of the current proposal are to: 1) develop a control system for a wearable artificial lung featuring sweep gas servoregulation to adjust CO2 removal based on patient needs; and, 2) evaluate the control system in an animal model. At the completion of this project, we expect to be ready to integrate the developed control system with various artificial lung systems that will, for the first time, enable large changes in patient activity during rehabilitation and daily life.